The distribution of trace metals in alluvial sediments depends on their natural background concentrations, and on the dynamics of contemporary depositional and erosional (mainly flood-induced) processes. Geological and geochemical investigations were carried out in the valley of Vistula River near Magnuszew (central Poland). Sediment samples were collected from a depth of 35 cm and comprise sediments of all defined geomorphological features. Identification and geological interpretation of the morphodynamic sediment features was supported by aerial photographs and high-resolution satellite images. These studies revealed that the distribution of trace metals is closely linked to the morphogenesis of the alluvial floodplain. The highest concentrations of Cu, Co, Zn, V, Cr and Ni were observed in crevasse-splays deposits. By contrast, Sr, Pb and As were concentrated in deposits which fill oxbow lakes (partly infilled with organic deposits). The lowest concentrations of trace metals were detected in flood sediments deposited within erosional troughs. The geomorphological and sedimentological history of the fluvial features explains the pattern of heavy metal distribution on the current floodplain surface.

We analysed the genetic structure of 33 populations of the root vole (tundra vole, Microtus oeconomus, Pallas, 1776) inhabiting their typical habitats, located at different distances from the southern boundary of the species' range (52°14 0 -53°56 0 N) in eastern Poland. We determined its phylogeographic pattern as well as the possible occurrence of a small, local high-latitude refugium of this species in southern Poland, previously suggested in palaeontological studies. 908 bp of cytochrome b sequences were analysed from 439 root voles, and 21 mtDNA cytb haplotypes belonging to the Central European (CE) phylogroup were found. Haplotype diversity in the examined populations varied between 0 and 0.872 (mean: 0.425 AE 0.332), while nucleotide diversity ranged between 0 and 0.62% (mean: 0.235% AE 0.217). Within the CE phylogroup of M. oeconomus, we identified with high bootstrap support a newly separated group of M. oeconomus that evolved from CE, denoted CE-PL S. This group is located in the southern and central part of eastern Poland and most likely diverged from phylogroup CE in a small, cryptic refugium situated in southern Poland, in the Krak ow-Cze z stochowa Upland and/or the Holy Cross Mountains during the LGM and Younger Dryas.

Permeability characterizes the ability of rocks to store and transport natural gas, crude oil and reservoir fluids. Permeability heterogeneity of reservoir rocks, including dolomites, results from overlapping geological and physicochemical processes. The permeability study of gas-bearing dolomites was carried out on the Lubiatów hydrocarbon deposit (Poland), located at the Ca2 carbonate platform toe-of-slope, which is a prospective area for hydrocarbon exploration in Europe. Due to the complicated rock textures and overlapping alteration processes, including secondary crystallization or dissolution of minerals, the permeability of the deposit is variable. Studies of dolomites from a depth of 3242–3380 m show high mineralogical diversity; the percentage of dolomite ranges from 79% to 95% with a variable content of other minerals: anhydrite, gypsum, quartz, fluorite, plagioclase and clay minerals. The porosity variability ranges from 4.69% to 31.21%, depending on the measurement method used. The mean permeability value is 35.27 mD, with a variation range of 0.9 to 135.6 mD. There is neither change in permeability with depth and mineral composition, nor a direct relationship between porosity and permeability.

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ABSTRACT:Falkowska, E., Falkowski, T., Tatur, A. and Kałmykow-Piwińska, A. 2016. Floodplain morphodynamics and distribution of trace elements in overbank deposits, Vistula River Valley Gorge near Solec nad Wisłą, Poland. Acta Geologica Polonica, 66 (3), 541-559. Warszawa.Geological and geochemical investigations were carried out in the floodplain of the Vistula River Valley gorge near Solec nad Wisłą (Małopolska Gorge of the Vistula River). Geological mapping was supported by DEM and remote sensing analysis. Sediment samples were taken from depths of 0.5 m and 1.5 m from all geomorphological features identified. The geochemical analysis included determination of Cr, V, Sr, Ba, Ni, Cu, Co, As, Pb and Zn concentrations. Results indicate that the main factors affecting the pattern of features in the floodplain of this area are (1) the highly dynamic flood flow in the narrow section of the gorge and (2) the relief of the top surface of the sub-alluvial basement. The variable concentrations of trace elements are closely related to the floodplain features. Their concentrations can be considered as valuable geochemical proxies that enable a more thorough reconstruction of the sedimentary evolution of the Vistula River Valley and other similar river valleys, especially in gorge sections.